Motor-propelling mechanism for boats



Oct. 28,1930. G. GRIFFITH 1,780,075

MOTOR PROPELLING MECHANISM FOR BOATS Filed Oct. 14, 1929 s Sheets-Sheet 1 25 T 23 7 g 5 \ll: my 54\ s' s W W :5 I 1 22 g. 1 4,5 11 Q Will Oct. 28, 1930. GRlFFlTH 1,780,075

MOTOR PROFELLING MECHANISM FOR BOATS Filed 001:. 14, 1929 a Sheets-Sheet 2 Oct. 28, 1930. 5. GRIFFITH 1,780,075

MOTOR PROPELLING MECHANISM FOR BOATS Filed OCt- 14, 1929 3 Sheets-Sheet 3 Patented Oct. 28, 1930 UNITED STATES PATENT OFFICE GEORGE GRIFFITH, OF SILVERMERE. COBHAM, ENGLAND, ASSIGNOR OF ONE-HALF TO THE HOYAL BODY CORPORATION (1928) LIMITED, 0]? WEYBRIDGE, ENGLAND, A. COR- PORATION OF GREAT BRITAIN MOTOR-PROPELLING MECHANISM FOR BOATS Application filed October 14, 1929, Serial No. 399,611, and in Great Britain October 13, 1928.

The principal object'of the present invention is to provide an improved boat propulsion system of the type comprising a fixed inboard motor and a detachable pivotally mounted outboard transmission unit WhlCl] carries the propeller and may also be used for steering purposes. More particularly the invention is intended to'provide a transmission unit of this kind for use in conjunction with a fixed drive shaft extending from the motor to the hull.

A further object of the invention is the provision of a releasable connection such as a claw clutch in. some part of the transmission gear. as between the drive shaft and a short extension shaft in the upper part of the housing of the transmission unit.

The invention is further concerned with mechanism for locking the unit to the hull and for automatically releasing the same under the efiects of impact upon say a submerged obstacle: with improved gear 'for swinging the unit up out of the water at will and with improved steering gear.

These and other objects will now be more fully explained by reference to the accompanying drawings illustrating examples of transmission unit according to this invention. Figure 1 is a side elevation of one form of unit.

Figure 2 is a rear sectional elevation on the line IIII of Figure 1.

Figure 3 a side elevation of a modified form of unit.

Figure 4 a similar view of a second modification.

Figure 5 a similar view of a third modification.

Figures 6 and 7 similar views of a part of the unit shown in Figure 5 in different positions and Figure 8 is an elevationof another modification.

Referring more particularly to Figures 1 and 2 of the drawings the transom 1 of the boat carries a metal plate 2 secured to it by bolts 3 and provided with hook shaped brackets 4. In the hooks 4 lies a stout round rod 5 the ends of which are fixed in the T section side arms 6 of a frame completed by cross pieces 7 and 8. This frame bears on the back of the boat and serves to transmit the propeller thrust thereto. Also fixed on the rod 5 is a central arm 9 in the form of an upward extension of the uppermost or cap portion 10 of the mechanism housing. As may be seen from Figure 1, this portion 10 of the housing is a casting having the shape of a. vertical cylinder intersected by horizontal cylindrical parts or bosses 11 located axially of the boat. These cylindrical parts 11 accommodate appropriate bearings 12 for a short transmission shaft 13 provided at one end with one half of a releasable coupling 14 such as a dog or other type of clutch or the like. With the mechanism in the 'position illustrated said half of the coubrought through the hull above the water line so that no stufling boxes or other packing devices are required. Since the engine position is not bound by the location of the screw, it may be installed in the rear of the boat, leaving the remainder of the hold free, or in any convenient position from which the drive shaft 15 may be carried through the hull. Automobile engines may thus be utilized with remarkably little (liiiiculty in motor boats or as auxiliaries in sailing vessels.

Towards the end of the shaft 13 remote from the coupling 14 is mounted a bevel wheel 16 meshing with a bevel wheel 17 on a vertical shaft 18 journalled in ball bearings 19 in a downward extension 20 of the housing portion 10. Said downward extension 20 fits in an upward extension 21 of the lowermost portion 22 of the housing. Said upward ex-' sion 20 and the intermediate housing portion 23, 24. A spacing ring 26 is interposed between the cap portion of the housing 10 and the last mentioned portion 23, 24. At any desired level the housing parts 23, 24 are shaped to receive a worm 27 on a shaft 28 journalled therein and provided at the rear end with some form of releasable coupling or ,clutch 29, for connecting it with a steering shaft 30 carried through the transom of the boat and operated from inside the latter. This worm 27 engages a worm wheel 31 formed on the upward extension 21 of the lowermost housing portion 22 so that steering movements can be transmitted to said lowermost housing portion 22. The use of a worm and worm wheel for steering purposes has the advantage that any reaction upon the housing caused by the propeller rotation or otherwise cannot result in movement of the steering gear as the non-return properties of the worm gear preclude this.

Extending downwardly in the housing portion 22 is a shaft 32 forming a prolongation of the shaft 18 with which, for constructional reasons, it has a releasable connection at 33. Said shaft 32 is journalled in ball bearings 34 in the housing portion 22 and at its lowermost end carries a bevel wheel 35 meshing with a bevel wheel 36 on a short horizontal propeller shaft 37. The bearings 38 for this shaft are contained in a horizontal cylindrical part 39 formed on the housing portion 22. To the lower surface of the part 39 is secured a fin 40 representing additional steering surface. The lower housing portion, at least, is streamlined as shown and is provided with the customary cavitation fin 41 above the screw 42.

To prevent any possibility of lateral movement of the mechanism. lugs 43 are provided on the transom 1 and engage the side mem bers 6. Particularly for reversing purposes it is then convenient to furnish said lugs 43 with releasable catch or lock devices (not shown) to prevent undesired swinging of the mechanism about its suspension. Having regard to the nature of the suspension means 4. 5 it will be appreciated that the mechanism although securely mounted upon the back of the boat can be readily lifted out and removed or may be swung to a horizontal position without interfering with the engine, the shaft connections 14 and 29 offering no hinderance thereto. On replacement of the mechanism in position. re-engagement of the operative connections is effected with equal facility. This ready detachability is of obvious advantage in the case of sailing vessels employing such mechanism for use with an auxiliary engine. In the case of normal motor boats it enables disturbance of the propeller to be avoided when the boat settles down on a mud or other bed or when the boat is being pulled up or down a beach. V

Figure 3 indicates more or less diagrammatically one form of simple mechanical gear for swinging the mechanism up out of the water. This consists of an arcuate rack connected to the frame 6, 7, 8 and passing through the back of the boatto engage interior operating means such as a handle 51 connected by gears 52 with a pinion 53 meshing with the rack 50. If desired, a locking arrangement can be employed for holding up the mechanism or for setting it, and with it the screw, at a required angle. In the arrangement shown in Figure 3 a modified form of stecril'ig gear is also provided. A tiller rope 54 (as illustrated), or a tiller chain, associated with a steering wheel or the like in the boat passes rearwardly over guide wheels 55 on the side members 6 and thence around a pulley or sprocket 56 fixed on the upward extension 21 (Figure 2) of the housing portion 22 in the position occupied by the ring 26 in that figure. Naturally if occasion demand, the worm wheel 31 may also be located at this level Figure 8) instead of in the position shown in Figure 2. The. disposition of the steering gear at said level has the advantage that the same is located well above the surface of the water, so that. any perforation in the hull for said gear needs no special packing devices.

A simple alternative for the arrangement shown in Figure 3 employs. in place of the pulley 56, a bevel wheel meshing with a bevel wheel on a short sleeve-shaft which surrounds the shaft 13 and has a clutch connection with a steering sleeve shaft surrounding the drive shaft 15.

In the modification illustrated in Figure 4, the upper part of the housing 10 is fixed to the transom l and the remainder of the housing is pivotally mounted thereon at 60. lVith this arrangement the shaft 18 will contain a releasable coupling, such as the claw clutch 61, to enable separation of the housing portion 23, 24 from that of 10. A rclear able lock or catch device 62 is employed for securing said two portions together when the mechanism is in position. In this embodiment the use of a rope 63 passing inboard over a guide wheel 64 is indicated for permitting the mechanism to be swung up as required.

In order to prevent damage to the screw by underwater obstacles or by a shallow bottom it may be desirable to make the mechanism capable of swinging up out of the way of such obstacles of its own accord. \Vhilc the constructions already described can be readily modified for this purpose, Figures 5, 6 and 7 illustrate a simple arrangement, which may be employed. The unit itself is similar to that of Figures 1 and 2 except that the suspension means consist simply of a pair of curved arms fixed to the rod 5, which is supported as before, and to the loJ ll l

housing portion 10. The thrust is transmitted to the boatby a frame 71 integral with the housing portion 23. Pivoted on said frame 71 or, as shown, on the part of the housing 23 enclosing the worm 27 (of Figures 1 and 2) is a lever, one arm of which takes the form of a claw or hook 72 while the other 73 is pivotally connected to a rod 7 pivoted to an operating handle 75; the latter is rotatably mounted on the rod 5. The claw 72 is arrangedto co-operate with an eyelet 76 secured to the transom of the boat and is preferably designed in such a manner as to facilitate the drawing in of the mechanism close against the back of the boat. This is not always a simple matter as with some combinations of transom 1 and propulsion unit, the latter may tend to hang slightly I away from the transom. For this purpose,

therefore, the surface of the claw 72 which engages the eyelet 76 is made to exert a certain cam effect. When the mechanism is being placed in position the linkage 72, 7 3, 74, 75' is in the state shown in Figure 7 so that the point of this claw comes to lie just above the eyelet. The handle 7 5 is then moved to the position shown in Figure 5, forcing the claw 72 into the eyelet 76 and drawing the frame 71 close to the transom 1 owing to the slight cam shape of said claw. Under all normal circumstances the engagement between the claw 72 and eyelet 76, which may be provided with a flat spring 77 to grip the hook 72 elastically, is sutlicient to secure the mechanism in position.

If, however, an obstacle is met with or, say, the boat runs into a shallow beach, some part of the housing portion 22 or the surface 40 will be encountered first and the shock of a serious obstacle will be more than suflicient to rotate the lever 72, 7 3 and the handle 75 in a clockwise direction and thereby to free the mechanism to swing up, under the shock, to a position in which the screw is safe from damage by the obstacle. Alternatively. a locking arrangement such as that described might be controlled by a simple trip arrangement disposed in front of the mechanism in such a way as to be tripped by obstacles of the kind referred to.

For reversing purposes it is necessary to be able to make the connection 72, 7 (i incapable of becoming released due to the pull of the screw tending to rotate the mechanism about the suspension point. It will be noted that in Figure 5 the linkage 74, 75, is ust short of a dead centre position. If the boat is to be put into reverse or if the mechanism is to be locked in position for any other reason, the handle-75 is pulled over until the linkage 74, 7 5 is on the other side of said dead centre position Figure 6). This may be facilitated by the provision in the claw of a notch 78 into which the eyelet seats in its extreme position. Naturally, once the dead centre has been passed, no tendency to rotate the mechanism back about its suspension point can release the connection 72, 76, as the pull exerted on the rtd 7 4 is ineffective for releasing the handle 75.

The handle 75 may be designed if desired, to co-operate with the reversing lever. In the arrangement illustrated, in Figure 6, the cap portion 10 of the housing is enlarged slightly to accommodate a simple reversing gear operated by a reversing lever 79. In this case the lever 79 may be provided for the purpose stated with a lug 80 which, when said lever 79 is moved to the reverse position,

in the upper housing portion 23 to a limited extent. A collar-80 on the extension 21 nor mally seats in the recessed upper surface of two arms 81 which embrace said collar over an are greater than a semi-circle and thus grip the collar when seated therein. These arms 81 are the forked ends of a member 82 hinged at .83 to the transom 1 of the boat and normally held in a position at right angles thereto by a powerful compression spring 84 bearing on an upwardly extending lug on a bolt 87 passing freely through the lug 85 into the transom.

A sleeve of rubber 88, or alternatively a compression spring, is interposed between the collar 80 andthe lower edge of the housing 23. This allows of upward movement of the collar 80 against the resilient resistance of the sleeve or spring 88. Upward movement will be caused by contact of the fin 40 with obstacles such as have been referred to above so that the collar 80 is automatically released from the grip of the arms 81 when danger threatens the propeller. The hinged. arrangement of the member--82 is necessary to allow the unit to be released and swung up at will. For this purpose said member 82 can be depressed out of engagement with the collar 80 by means of the lever 89 I In the foregoing description it has been assumed that the mechanism is arranged at the rear and on the transom of the boat; this is not necessarily the case. For instance if used as a dismountable auxiliary drive for a yacht, it mightbe more convenient to arrange the mechanism on one side and to suspend the same from some part of the hull other than the transom. It is important only that there should be a suitable point for applying the propeller thrust and steadying the mechahull is not convenient for the application of a thrust by a plane frame. 6, 7, 8 of the nature illustrated, either a bearing frame may be built up on the hull or the frame- 6, 7, 8 of the mechanism may be adapted to the shape of the hull the latter course being pieferable when it is undersirahle to interfere with the existing lines of the vessel. \Vhere employed as an auxiliary on a sailing vessel,'moreover, the ready detachability of the unit then leaves the vessel perfectly free to be sailed in the ordinary way. In some cases the use of swan neck suspension arms in the place of the simple brackets 4 (Figures 1 and 2), may be of advantage for instance in overcoming the diiiiculties encountered withexist-ing hulls.

I.clain1:

1. Boat propulsion system comprising a fixed inboard motor, a fixed drive shaft extending from the motor to the hull, a detachable outboard transmission unit carrying the propeller, a pivotal suspension for said unit and a releasable connection between the drive shaft and the transmission gear in said'unit. s

2. Boat propulsion system comprising a fixed inboard motor, a fixed drive shaft extending to the hull and a detachable outboard transmission unit consisting of a housing with a pivotal suspension from the hull, a shortiextension shaft in the upper part of said housing having a releasable connection with the drive shaft, downwardly extending transmission gear within the housing and a propeller shaft in the lower part of said housin".

5. Boat propulsion system consisting, in combination with a fixed inboard motor and drive shaft extending to the hull, of a detachable outboard transmission unit comprising transmission gear having a releasable "connection with the drive shaft, an upper housing portion pivotally mounted in a detachable manner upon the hull, a lower housing portion carrying the propeller and rotatable in relation to the upper portion and steering means for imparting rotation to said lower portion of the housing.

4. Boat propulsion system comprising a fixed inboard motor with a driving shaft extending to the hull, an outboard housing carrying the propeller and containing transmission gear having a releasable connection with the drive shaft and means for ivotally supporting said housing in a detacha le manner consisting of a suspension bar carrying said housing and a slotted support upon the boat hull for receiving said bar.

5. Boat propulsion system consisting, in

combination with a fixed inboard motor and drive shaft extending to the hull, of a detachable outboard transmission unit comprising transmission gear having a releasable connection with the drive shaft, a housing for said gear, pivotal suspension means at the upper part of said housin and a locking device adapted to hold the ower part of said housing tothe hull.

6. Boat propulsion system consisting, in combination with a fixed inboard motor and drive shaft, of an outboard unit com rising transmission gear having a releasab e connection with the drive shaft, a housing for said gear, a pivotal suspension for said housing, locking means normally holding the unit to the hull and trip mechanism operative to release said locking means automatically.

7. Boat propulsion system consisting, in combination with a fixed inboard motor and drive shaft, of an outboard transmission unit comprising transmission gear having a releasable connection with the drive shaft, reversing mechanism incorporated in said gear, a pivotally suspended housing, a connection normally holding the housing to the hull, trip mechanism operative to release said connection automatically and locking means associated with the reversing mechanism and adapted to prevent the trip mechanism from automatically releasing the connection when the boat is in reverse.

8. Boat propulsion system consisting, in combination with a fixed inboard motor and drive shaft, of a pivotally suspended detachable outboard transmission unit comprising a housing, transmission gear within said housing havin a releasable connection. with the drive shaft, steering mechanism within said housing operative upon a rotatable part thereof and a releasable connection between said mechanism and inboard steering gear.

9. Boat propulsion system consisting, in combination with a fixed inboard motor and drive shaft, of a detachable outboard transmission unit comprising transmission gear having areleasable connection with the drive shaft, an upper housing portion pivotally suspended from the hull, a rotatable lower housing portion having an upward extension journalled in the upper housing portion and a worm wheel upon said upward extension meshing with a worm associated with inboard steering gear, said worm and worm wheel being enclosed in the upper portion of the housing.

G. GRIFFITH. 

